The continued development of a crude flagella (CF) vaccine for establishing active immunity of Vibrio cholera will be pursued. A method for storage of the vaccine will be sought to maximize the shelf life of the vaccine. Maintenance of the integrity of the sheath proteins as well as the classical approaches to vaccine stabilization will be examined. The parameters affecting the level of immunity to cholera achieved with CF vaccine will be examined in detail using animal models. The effects of such factors as total amount and concentration of antigens in the vaccine administered, and the immunization schedule will be investigated. The possibility of oral immunization will not be disregarded. The efficacy of the CF vaccine will be compared with commercial whole cell and toxoid preparations. The ability of the vaccines to confer immunity will be evaluated in both the rabbit ileal loop and the infant mouse models. Temporal characteristics of the active immunity resulting from use of these vaccines will be determined. Gut fluids of immune animals will be assessed for the identification of the antigenic specificities of antibody induced by the CF and the commercial vaccines. Passive immunization experiments will be done to determine if serum antibody participates in cholera immunity and inhibition of protection experiments will be used to evaluate the role of IgG and IgA in local gut immunity to cholera.